When I first started using Shapeways - and ever since - it was always my belief that NO files - except for earrings and cufflinks - could have more than one object in it. The only way around this was for the user to attach sprues to each piece thereby making it "one" model.

I brought this fact up to someone in the Forums and was told that, no, in fact with WSF it was possible to have multiple parts in one file.

I started looking around the stores here and found quite a few people have files with multiple models NOT joined by sprues and available in different materials including stainless steel. The largest model I found had 20 separate pieces in Ultra Detail!

In questioning this with Customer Service I'm told that if the "Production Facility" deems there to be too many then it gets rejected. This doesn't make sense. That leaves too much open to interpretation as to what is "too many".

So my question to you is: Are you one of these people with multiple parts in one file and what problems have you encountered getting prints made?

We are actually working on a blog post about this for everyone but in the meantime, here is the bulk of it:

In WSF, we can handle multiple parts in one STL, particularly if they are many small parts - we want to be friendly towards people creating complex products that are made of multiple parts (ie/ puzzles) and its not a problem for us to put a cage around many small items (like miniature battleships), so we allow this.

3D printing metals is costly, and we pay per part so we don't want to encourage multiple parts in one STL (again, the exception to this is cufflinks and earrings in Silver, as we want to make it easy for people to create products and these work as a set) in metals. We are working on InShape2 to enable this automatically, but right now we manually check files, and we are not set up to detect multiple parts per STL in an efficient manner. We do pay for each part we produce so we rely on our customers to do the right thing and only put one file per STL. For the most part, people do only have one part per STL.

The future we see for Shapeways is enabling people to make products. Sometimes a part is a product (a ring) but more often that not, a product is comprised of multiple parts (a puzzle), so we want to make it easy to do multiple parts per STL, with a corresponding handling fee that is fair for everyone. This solution is a few months off, so in the meantime, we hope you exercise your judgement so we don't have to reject too many models. It is currently up to the production teams judgement to reject a model or not. Obviously when we reject models this causes delays and customers get unhappy, thus we're trying to encourage people to *not* pack multiple parts in one STL and risk rejection.

I hope that is helpful, and you can work with us towards the fairest solution for all.